Imagine a scene from a worst-case scenario survival guide. You are on vacation at the beach, when the sky darkens. On a collision course, a massive asteroid speeds toward Earth. In what may be your last moments, you look around at the sunbathers, seagulls surfing the sea breeze, trees on the bluff, and the rocky tide pools at the shoreline. Life as you know it is about to change  but how? Some species on Earth will survive the impending mass extinction, but others are doomed. Who will live and who will die?

Dr. David Jablonski is seeking the answer to this very question. As a paleontologist at the University of Chicago, David researches patterns of diversification and extinction in the fossil record. He's particularly drawn to big questions about the history of life. How do evolutionary explosions occur? How do extinctions actually work? Why do some species survive mass extinctions, while others perish? Using research methods more typical of historians and statisticians than paleontologists, David has uncovered a surprising answer to this last question  one with important implications for conservation today.

In this research profile we will explore these key questions:

What are mass extinctions?

How can we investigate hypotheses about past mass extinctions?

How have mass extinctions shaped the history of life?

How can understanding the history of life influence conservation strategies today?

Development of these materials was supported by the National Aeronautics and Space Administration under SPO award No. 022254-003. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Aeronautics and Space Administration; Photo provided by the University of Chicago